石羊河流域降水稳定同位素变化的区域差异

为了了解干旱内陆河流域降水稳定同位素变化过程及其影响因素,基于石羊河流域荒漠区、绿洲区和山区8个站点2013年7月至2014年7月,497个降水样品氢氧稳定同位素数据及相应气象数据,研究了石羊河流域降水稳定同位素的时空变化、环境效应以及降水水汽来源.结果显示：石羊河流域局地大气水线斜率和截距表现出夏低冬高的变化趋势;降水稳定同位素表现出夏高冬低的变化趋势,从荒漠区、绿洲区到山区,稳定同位素值随海拔升高而降低,海拔效应为-0.22‰/100m,这是温度效应的另一种体现;流域降水稳定同位素表现出显著的温度效应,温度效应为0.43‰/℃,在天气尺度下受季风水汽和降水淋洗过程的影响表现出降水量效应;流域降水来源主要受西风水汽控制,夏季也会会受到季风水汽影响,冬季也受到极地气团影响.     

洱海流域乡镇尺度上人类活动对净氮输入量的影响

人类活动引起的氮素过量输入已经成为引起水体富营养化及其他生态危害的主要原因.为了研究人类活动对流域氮素的影响,本文基于洱海流域16个乡镇行政单元的统计数据,考虑流动人口的影响,利用NANI模型估算洱海流域乡镇尺度的人类活动净氮输入量(net anthropogenic nitrogen inputs,NANI).结果表明,2014年洱海流域NANI总量为29.81×10~3t,单位面积输入强度(以氮计)为10 986 kg·(km~2·a)-1,显著高于我国平均水平.当地旅游人口带入的食品氮输入为0.26×10~3t,占到了流域居民食品氮输入的8%.从氮素的输入量的构成来看,肥料输入是最大的贡献源,占到了流域净氮输入的47%,其次为食品饲料的净氮输入.在空间分布上,乡镇单元的NANI分布呈现明显区域化特征,从流域整体上看呈现北高南低的特点.耕地或人口集中的乡镇NANI强度偏高,洱海流域具有较大的氮素污染风险.     

GENERATING DESIGN HYDROGRAPHS BY DEM ASSISTED GEOMORPHIC RUNOFF SIMULATION: A CASE STUDY1

ABSTRACT: The geomorphic instantaneous unit hydrograph (GIUH) may be one of the most successful methodologies for predicting flow characteristics in ungauged watersheds. However, one difficulty in applying the GIUH model is determination of travel time, and the other difficulty is the large amount of geomorphologic information required in the study watershed. Recently, using the kinematic-wave theory Lee and Yen (1997) have analytically determined the travel times for overland and channel flows in watersheds. The limitation of using an empirical velocity equation to estimate the runoff travel time for a specified watershed is then relaxed. To simplify the time-consuming work involved in geomorphic parameter measurement on topographic maps, the GIUH model is linked with geographic information systems to obtain geomorphic parameters from digital elevation models. In this paper, a case study performed for peak flow analysis in an ungauged watershed is presented. The geomorphic characteristics of the study watershed were analyzed using a digital elevation model and were used to construct the runoff simulation model. The design storm was then applied to the geomorphic runoff simulation model to obtain the design hydrograph. The analytical procedures proposed in this study can provide a convenient way for hydrologists to estimate hydrograph characteristics based on limited hydrologic information.     

HYDROLOGIC BALANCE OF LAKE CHAPALA (MEXICO)1

ABSTRACT: Lake Chapala, whose primary tributary is the Río Lerma, is the largest freshwater lake in Mexico and for the past 95 years has maintained an average storage capacity close to 6,700 Mm³. Starting hi the early 1970s, the Lerma-Chapala basin rapidly industrialized. In response to these upstream anthropogenic activities, the fisheries, aesthetics, and water quality of Lake Chapala have decreased as a consequence of the increasing chemical and biologic pollutants mainly from the Río Lerma. Additionally, the growth of Guadalajara has resulted in increasing potable water demands on the lake to satisfy a population currently greater than 4.5 million. During the 1980s, the outflow and water losses from the lake substantially exceeded the inflow and other water contributions. In this paper, the recent behavior of the hydrologic and bathymetric parameters of Lake Chapala are summarized and some important physical stresses on the system are identified. The focus of this work is the 1934–1989 period, and it is shown that starting around 1980 some of the main contributors to the lake water balance were severely perturbed and the lake reached its second lowest recorded level. The disturbances of the system are so severe that the entire regional ecosystem could be irreversibly affected in the near future.     

Integrating wetlands and riparian zones in river basin modelling

Wetlands, and in particular riparian wetlands, represent an interface between the catchment area and the aquatic environment. They control the exchange of water and related chemical fluxes from the upper catchment area to surface waters like streams and lakes. Their influence on water and nutrient balances has been investigated mainly at the patch scale. In this study an attempt was made (a) to integrate riparian zones and wetlands into eco-hydrological river basin modelling, and (b) to quantify the impacts of riparian wetland processes on water and nutrient fluxes in a meso-scale catchment located in the northeastern German lowland. The investigation was performed by analysing hydro-chemical field data and applying the eco-hydrological model SWIM (Soil and Water Integrated Model), which was extended to reproduce the relevant water and nutrient flows and retention processes at the catchment scale in general, and in riparian zones and wetlands in particular. The main extensions introduced in the model were: (1) implementation of daily groundwater table dynamics at the hydrotope level, (2) implementation of water and nutrient uptake by plants from groundwater in riparian zones and wetlands, and (3) assessment of nutrient retention in groundwater and interflow. The simulation results indicate that wetlands, though they represent relatively small parts of the total catchment area, may have a significant impact on the overall water and nutrient balances of the catchment. The uncertainty of the simulation results is considerably high, with the main sources of uncertainty being the model parameters representing the geo-hydrology and the input data for land use management.     

Strong effects of various incidence and observation angles on spectrometric assessment of plumage colouration in birds

The assessment of plumage colouration has become a common procedure in many ornithological studies, especially after the discovery of differences between avian and human visual systems, namely the avian ability to perceive ultraviolet wavelengths. There are many techniques available for plumage colour assessment. Nevertheless, unidirectional reflectance spectrometry seems actually to be the method of choice and is used in most studies. The active avian visual communication skills, the physical characteristics of the plumage surface and the birds’ body shape prompted us to study plumage colouration with different angles of incidence and observation by bidirectional reflectance spectrometry. In this study, we explore the effect of different angles of incidence and observation, on a single plane of incidence, on the reflectance spectrometric assessment of five differently coloured body regions of the blue fronted Amazon parrot (Amazona aestiva). Measurements were made using a AVS-USB2000 spectrometer with a DH-2000 light source and two different reflection probes (bifurcated fibre optic probe and a specially designed fibre holder). The results of this study illustrate clear angle dependence of colour parameters in differently coloured non-iridescent plumage regions of the blue fronted Amazon parrot. Our results may have direct implications on the observed transmitted information of display and its associated predation risk (trade-off) in birds, but also in other animals. Moreover, the results show that unidirectional reflectance spectrometry alone may be a rather limited procedure to quantify and compare true colour of a complex surface such as birds’ plumage. Therefore, slight but behavioural important characteristics of plumage pattern may remain undiscovered with this method.     

黑河流域生态功能区划及其保护

根据整体性、主导性、综合性原则 ,运用叠置法 ,将黑河流域划分为 3个生态功能区、9个亚区 ,分析了各个功能区的生态特征及存在的生态问题。分区提出了生态保护措施 ,并探讨了黑河流域生态保护及管理对策。     

Solute transport in crystalline rocks at Äspö — I: Geological basis and model calibration

Water-conducting faults and fractures were studied in the granite-hosted Äspö Hard Rock Laboratory (SE Sweden). On a scale of decametres and larger, steeply dipping faults dominate and contain a variety of different fault rocks (mylonites, cataclasites, fault gouges). On a smaller scale, somewhat less regular fracture patterns were found. Conceptual models of the fault and fracture geometries and of the properties of rock types adjacent to fractures were derived and used as input for the modelling of in situ dipole tracer tests that were conducted in the framework of the Tracer Retention Understanding Experiment (TRUE-1) on a scale of metres. After the identification of all relevant transport and retardation processes, blind predictions of the breakthroughs of conservative to moderately sorbing tracers were calculated and then compared with the experimental data. This paper provides the geological basis and model calibration, while the predictive and inverse modelling work is the topic of the companion paper [J. Contam. Hydrol. 61 (2003) 175].The TRUE-1 experimental volume is highly fractured and contains the same types of fault rocks and alterations as on the decametric scale. The experimental flow field was modelled on the basis of a 2D-streamtube formalism with an underlying homogeneous and isotropic transmissivity field. Tracer transport was modelled using the dual porosity medium approach, which is linked to the flow model by the flow porosity. Given the substantial pumping rates in the extraction borehole, the transport domain has a maximum width of a few centimetres only. It is concluded that both the uncertainty with regard to the length of individual fractures and the detailed geometry of the network along the flowpath between injection and extraction boreholes are not critical because flow is largely one-dimensional, whether through a single fracture or a network. Process identification and model calibration were based on a single uranine breakthrough (test PDT3), which clearly showed that matrix diffusion had to be included in the model even over the short experimental time scales, evidenced by a characteristic shape of the trailing edge of the breakthrough curve. Using the geological information and therefore considering limited matrix diffusion into a thin fault gouge horizon resulted in a good fit to the experiment. On the other hand, fresh granite was found not to interact noticeably with the tracers over the time scales of the experiments.While fracture-filling gouge materials are very efficient in retarding tracers over short periods of time (hours–days), their volume is very small and, with time progressing, retardation will be dominated by altered wall rock and, finally, by fresh granite. In such rocks, both porosity (and therefore the effective diffusion coefficient) and sorption K_ds are more than one order of magnitude smaller compared to fault gouge, thus indicating that long-term retardation is expected to occur but to be less pronounced.     

滇池宝象河流域全面产流与降雨关系初步研究

在进行滇池宝象河流域入湖污染负荷总量核算时,涉及流域的水量平衡计算,地表径流和地下径流是两个重要的环节,两者联系密切,并且在水循环过程中相互转化。不是所有的降水都能补给地下水,进而产生地表径流,只有当降雨量大于某一临界值时,才有可能产生地表径流。全流域地表径流产生与降雨关系的试验研究,有助于分析当地气象因素以及降雨时段之初的包气带含水率和地下水埋藏深度,为污染负荷总量核算提供参考和借鉴。     

水生态分区管理国际经验与太湖流域应用研究

简述了国外水生态区的发展历程以及国外水生态区在建立生态系统数据库、制定差异化水质标准、开展河流生态监测及评价水体健康等方面进行的应用研究。通过对太湖流域水生态功能分区的研究，指出当前水环境管理存在的问题与水生态区管理的优势，提出应重点从水生态区监测、试点考核、评价、修复等具体操作层面开展应用研究，引导我国水环境管理从水化学指标逐步向水生态综合指标转变，推动建立以水生态系统健康为导向的水环境管理创新体制。